BLACK PIGMENTATION OF THE HEPATIC CELLS. BROWN ATROPHY.
In horse. With melanoma and atrophy, or without, pigment granules fill hepatic cells, liver becomes brown or black. In calves. In sheep. Apart from melanosis, the real cause unknown.
The accumulation of granules of black pigment in the hepatic cells has been noticed in old and worn out horses (Louis Blanc, Cadeac, Bruckmüller), in calves (Degive, Cadeac), and in sheep (Siedamgrotzky, Barrier). In horses it has been found in connection with atrophy, or in other cases, with melanotic tumors in other parts. In atrophic cases the liver is small, puckered, brown and dull, with a leathery appearance on section, and with the hepatic cells charged with pigment granules so that each acinus has a stellate appearance from the radiating lines of cells. This constitutes brown atrophy.
The second form which may be called melanotic liver, is not associated with atrophy, but is characterized by the crowding of the hepatic cells with black pigment granules, which fill up the protoplasm and crowd the still pale nucleus to one side. The affected portions become of a deep black.
In calves the pigmentation may be confined to the superficial portion of the liver (Degive).
In sheep pigmentation may be in the peripheral cells only of the acinus (Cadeac) but is about equally distributed on the surface, and throughout the interior of the liver, and may extend to the stroma of the gland (Siedamgrotzky).
Apart from the general causes of melanosis, benignant or malignant, no definite reason for this pigmentation has been assigned. The development of melanæmia and tissue pigmentation in man from malarious microörganisms suggests that other germs and their products may have a similar effect in the lower animals but nothing certain is known as to the true cause.
Apart from melanosis, it is not known that this pigmentation of the hepatic cells is of any essential pathological importance. It is important however for the veterinarian to be acquainted with the condition, that he may intelligently deal with such lesions whether seen in ordinary post mortem examinations, or in the course of meat inspection.
DILATATION OF THE GALL BLADDER AND BILE DUCTS.
Causes: obstruction of common bile duct, distoma, round worms, tæmiæ, gall stones, encrustations, inflammations, tumors, cicatrices, hydatids. Congenital absence. Ducts stand out on liver. Symptoms of colic, icterus, bile poisoning, marasmus. Treat the causative conditions.